Roofing materials need to be waterproof and are frequently used in multiple layers to convey a redundant water barrier. Underlayment materials are known which are applied to roof decking to provide a first layer of water-proofing. Additional roofing layers, such as roofing tiles, shingles, or asphalt roll roofing are then applied over the underlayment in order to increase the weather resistance of the roof and to achieve aesthetic effects. While various types of underlayment and finish roofing layers are known, additional alternatives remain desirable.